There are three basic goals during the remaining six months of the present grant. a) Firstly, we would like to know if periodic complex cells exist in the primate. If so, then our results would be more applicable to human visual psychophysics and to pattern recognition problems in man. Therefore, during the coming year we plan to study an old world primate - Java monkey, and a new world monkey - the owl monkey. b) We are also trying to determine how periodic complex cells might be assembled from antecedent neurons along the visual pathways. We are therefore, in the cat, studying the responses of representative simple cells and geniculate axons of each main subclass - bipartite, tripartite, on-center, off center etc. - to both single moving slits and to gratings. Based upon these results we are working on a model to see if periodic complex cells can be assembled from outputs of simple cells alone, geniculate axon alone, or whether it requires inputs from both genicualte axons and simple cells. c) Finally, we are studying non-periodic cells with both single slits and gratings to see how these cells may differ from periodic complex cells.